Currently, wireless communication is extensively utilized in various fields of applications, such as in homes, public places, or office areas. Consequently, there is a huge demand for high data-rate and bandwidth-efficient wireless transmission standards, such as 802.11 Wireless LAN, cellular LTE, and 5G. Accordingly, various concepts, such as linear amplification using nonlinear components (LINC) (also known as outphasing), are being used for highly efficient linear power amplification of wireless signals, for example RF signals.
Typically, in an outphasing transmit wireless system, an RF signal with varying amplitude (also referred to as “variable-envelope signal”) may be decomposed into two (or more) components with constant amplitude and different phases (also referred to as “constant-envelope signals”). Such constant envelope signals may be amplified by power amplifiers in an RF transmitter. The two amplified constant-envelope signals may be combined and transmitted by the RF transmitter, via a multi-antenna array, to an RF receiver.
In certain instances, there may be gain and/or phase mismatches between the two decomposed signals. Consequently, the linearity of the power amplifiers may be reduced and hence, may increase the error vector magnitude (EVM) of the RF signal. Further, such mismatch in gain and/or phase may result in IQ imbalance of the RF signal, thus deteriorating the signal quality. Thus, there is required an outphasing calibration that overcomes these deficiencies.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present disclosure as set forth in the remainder of the present application with reference to the drawings.